Method of and apparatus for producing rock wool



Jan. 17, 1928. LGSQSZS E. R. POWELL METHOD OF AND APPARATUS FOR PRODUCING ROCK WOOL Filed Jan. 5. 192'? 3 Sheets-Sheet 1 1,656,828 E. R. POWELL METHOD OF AND APPARATUS FOR PRODUCING ROCK WOOL Filed "Jan. 5. 1927 3 Sheets-Sheet 2 Jan. 17, 1928.

m Q @Q mw Q Jan 17, 192& 1,656,828

. E. R. POWELL METHOD OF AND APPARATUS FOR PRODUCING ROCK WOOL Filed Jan. 5. 1927 s Sheets-Sheet a Patented Jan. 17, 1928.

PATENT OFFICE- EDWARD R. IPOINELL OF ALEXANDRIA, INDIANA.

METHOD OF AND APPARATUS FOR PRODUCING ROCK WOOL.

Application filed January 5, 1927. Serial No. 159,228.

This invention relates to a method of, and

apparatus for producing a more stable and permanent rock or mineral wool; and with regard to certain other features to an improved felted and/or laminated product composed of said improved wool.

' Among the several objects of the invention may be noted the-provision of a method and apparatus for making arock or mineral wool which is substantially'"l'ree of sulphides. whereby the stability and permanency of the compounds com 'iosing the wool is increased; the provision of improved felting of said wool so as to obtain the strongest product possible and at the same time the maximum insulating efficiency which the material can maintain; the provision of adjustable apparatus adapted to produce said improved wool quickly and cheaply invarious thicknesses and textures and densities; and the manu facture of an improved product comprising a laminated insulating block, the insulating elliciency of which is greater than that of an equivalent solid block, especially in applications to damp and humid installations.

\ Other objects will be inpart obvious and in part pointed out hereinafter. I

The invention accordingly comprises the elements and combination of elements, features of construction, arrangementof parts. and the steps and sequence of steps which will be exemplified in the structure hereinafter described, and the scope of the. up

plication of which will be indicated in the following claims.

lathe accompanying drawings, in which are illustrated various possible embodiments of the invention,

Fig. 1 is a diagrammatic vertical section of a furnace, also showing certain desirable auxiliaries;

Fig. 2 is a diagrammatic vertical section of a blow chamber and includes also an en larged detail showing the preferred method of laminating the product;

Fig.3 is alateral section of said blow chamber taken on line 83 of Fig. 2;

Fig. 4 is a View similar to the enlargedportion of Fig. 3 but illustrates a modified form of the product-;'

Fig. 5 is a View similar to Fig. 4:, illustrating a second modified form, of the p roduct .3 and.an outlet flue 4. tom 5 of the cupola l are composed of fire proper.

Fig. (3 is a view similar to Fig. 4 illustrating a third modified form of the product; and

Fig. 7 is a fragmentary plan view'of a roller showing the application of sidewaru guides thereto;

Corresponding reference characters indicate cm'respomling parts throughout the sev-' eral views of the drawings.

eferring now more particularly to Fig. 1. there. is illustrated at numeral 1 a furnacc comprising, among other elements, a cupola equipped at. its upper end with a conventional hopper-and-bell charging door The walls and botbrick or other lire resisting materials at all points except around the melting and preheating zones, at which zones a water jacket 7 is used. The bottom (3 may be dumped in the conventional manner when it is desired to clean out the cupola 1. i

The lower end of the cupola communicates with a combustion chamber 9 and is provided with .an outlet 11 for permitting an elilux of molten material. Suitable t-uyeres 13 are provided in the jacket Walls of thecupola for controlling air flow to the charge,primarily for purposes of controlling the temperature of the cupola charge so that all of the charge does not melt down at once to block the draft.

In the present embodiment of the invention, the combustion chamber S) is of elongated form and slopes upwardly from the.

point 29 o if comn'mnication with the cupola The walls of this chamber Q are also provided with a water jacket 15 which may communicate with said jacket 7 of the cupola.

A closed water circulating system 17 including a circulating pump 19, drives water through the jackets 7, 15. A closed heat exchanger 21 serves to reclaim heat from the jacket water for use in other processes,

.not herein described. The purpose of the closed jacket water system is'to exclude the presence of harmful amounts of impurities which might cause a burning of the cupola wall plates by lowering the heat conductivity of said walls if the impurities became encrusted thereon. v m z 1 The surfaces of the combustion chamber 20 present, that is, in most locations.

- cupola 1.

- 9 and the preheating and melting zones of the cupola become lined during use with a layer of chilled sla At the upper of the combustion chamber 9 is provided a owdered fuel burner 23, preferably for ma the inlet air supply of which is drawn through an air preheater 25' by. a blower 24, which forces the air to the burner '23. The preheater 25 is placed in the conventional manner in the breeching of the flue 4, provided near the top of the The flame 30 of the burner 23 is directed down the chamber 9 and is provided with an excess of air for'purposes-to be described. Its normal tendency is to enter the cupola 1 and rise therein, the resulting heated gases finally passing out. at the flue 47. Oil, gas or other suitable fuels may'also be burned; but coal or coke is the most economical at The theory and operation'of the cupola is as follows:

Argillaceous limestone containing (broadly) silica, alumina, lime and magnesia (and a trace of sulphur as an inherent impurity),

or slag (containing higher percentages of sulphur as inherent impurities) is loaded into the cupola in lump size. It takes up the approximate position shown in Fig. l. g

It is to be understood that s0-.called rock woolis made directly from thejrock which contains only the slight trace of sulphur; while so-called mineral wool is made from the slag which contains the higher percentages of sulphur. In either case, however, the sulphur may become detrimental to the resulting wool product if the sulphur ispermitted to take a sulphide form, although a sulphate form is less harmfuls For instance, calcium sulphideis detrimental to the resulting wool composition be cause it tends to react with the dilute acids often found in the moisture of the atmosphere. This reaction gives of!" hydrogen sulphide gas which is soluble in the atmospheric moisture. Hence, if any -lar e percentage of sulphides of calcium or ot er ele-- ments are contained in the wool, it is rendered a substantially unstable composition or compound. Such/a composition is therefore not a permanent or desirable material for purposes of construction. The sulphides also corrode man metals when wet, which is highly undesirab e.

On the otherhand, sulphates of calcium or other elements are harmless in the wool because they do not render it an unstable composition." There is little or no tendency for the-action above described, to take place,

that is, due to the presence of calcium sulphate or other sul hates.

Inasmuch as su phur is a widely diffused element, resent in most fuels and many rocks (at east in traces), it is desirable that be carried out so that none of the sulphur will be reduced to the sulphide form or if already present as a sulphide, that it be oxidized to the sulphate form.

To carry the above principle into effect, the fuel'is burned in a region such that complete combustion takes place before the products of combustion contact with the raw material to be fused, that is, the fuel is burned in the separate combustion chamber 9, preferably with an excess of air; instead of being burned with the material (as has been done heretofore) by packing it into the cupola with said material. Hence substantially no reducing action takes place near the rock in the present invention. Incident-ally, the sulphur content of the fuel is prevented from being'added to that of the ..rock and product thereof, to aggravate the recited difliculties.

The combustionof the fuel from the burner 23 is substantially complete when the inlet 29*to the cupola is reached. The cupola may be called a fusion chamber. All of the sulphur in the fuel is oxidized to sulphur dioxide and sulphur trioxide gases which pass out of the flue 4 to the stack not shown) and do not contaminate the pro uct in passing through the rock. The carbon is oxidized to carbon dioxide, the carbon monoxide content in the cupola being low. This represents a saving in fuel, as the heat of combustion to carbon dioxide is much greater than that to carbon monoxide.

The excess of air ensures that the products of combustion will remain in oxidized form and will not be reduced b'y organic or like matter in the rock material being fired.

If no sulphur exists in the rock in sulphide f orm,'the above features alone avoid the presence of sulphides in the finished product. If sulphides are present, then another featureis used, hereinafter to be described.

The action of the hot gases in passing through the rock or slag in the cupola is to melt it down to a liquid rock which flows off at the outlet 11. i v I When sulphides are present in the raw rock or slag, it is'necessary to oxidize them to sulphates if a sulphide-free rock wool is to be obtained. This cannot always be accomplishedhy an oxidizing flame because heat may be received indirectly by the material, which will'melt andrun down to the outlet 11 without being oxidized. To prevent the above disadvantage, a fusible oxidizing agent'is introduced with the rock, slag or other raw materiah at the (ill oxidizing the sulphides present to sulphates.

As in the case of the excess air, it is desirable to use an excess of the above oxidizing agents so that the action is positively eomplete. All excess oxygen will bubble to the surface of the melt and pass oll' as a harmless gas.

.\s is illustrated in Figure. l. theliquid L'Utk trickles from the rock charge in the cupola and forms a pool from which the etllux at the outlet 11 is fed. As the charge in the cupola melts down, more raw rock may be fed in at the charging door 3. The fresh rock is preheated by the upflowing gases as said rock descends to the melting zone.

In the above manner a sulphide-free liquid rock is made to flow from the outlet 11.

In order to transform the liquid rock into the fluff y or wooly fibrous mass required for purposes of insulation, it is permitted to descend from the outlet 11 into the-path of a rapidly moving steam (or air) jet 31 issuing from a nozzle 33. For purposes of improving the .tinal product, underecrtain circumstances, a binder material is introduced into the nozzle by means of the secondary jet 34 to be projected with the jet 31. The rapidly moving steam of the jet 31 draws the precipitating melted matcrial out into innumerable fine atomized glassy threads at the forward end of many of which is formed a minute ball or drop. In settling down, most of the resulting fibers of rock or mineral wool lose the ball or drop; but whether attached or detached the small drops usually appear inthe resulting. mass of glassy threads, unless they are permitted to drop out.

ltremains to felt downthe rock wool and in the process permit the removal of many of the small drops.

The following method of felting is based on the fact that rot-l: or mineral wool comprises a brittle fiber and will not permit of tearing, remlingg" or reassembling, as is practicable in making textile and asbestos products; The strongest feltwhich can be made of roel-: wool is that which is naturally formed by the gentle and gradual pressure that the material exerts as it falls in the chamber into which it is blown by the steam jet. r

By felting in the above manner the miximum insulating efficiency of which the material is capable is obtained. This is be cause a maximum number of the fibers lie with their lengths parallel to the horizontal planes of the material. Rock wool, when felted in this way, comprises a pliable material whiclrmay be formed to fit various surfaces or into various recesses. Referring now more particularly to Figure 2, the improved method of felting will be described A blow chamber 35 is provided with an said channel.

the same direction. thereof is movable about the center of its I the wool to inlet mouth 37 adapted to receive the steam jet 81 which carries the spray of melted, atomized and fast hardening fibrous materials. An outlet 3!) for air and steam is provided ator near the top of said chamber 35.

Referring to Figure :3, it will be seen that the bottom portions ll of thechamlwr Z35 taper inwardly and downwardly in hopper form. Thee portions ll. have smooth sides and descend to regions in proximity to the upper reach of a moving conveyor belt 43. The portions ll and theends of the chamber 35 cooperate with said conveyor 43 in a manner such that the blown wool does not escape from the chamber before it is desired to have it do so. This is done by means of a, narrow channel I-Q-ot' width equal to the width of the layer of tinishedwool, which may be from two to eight feet or so.

The conveyor 4:3 is driven from a conven tional variable speed drive 45 and is adapted to carry the rock wool from the blow cl1amher by way of an opening 17.

Just above the conveyor and outside of the chamber is pivoted at 36 a roller-supporting frame A 9 which supports a plurality of roller axles 51.. These axles through suitable slots in the channel 4% and carry rollers 53 within the channel 441-. The rollers 53 are approximately the-width of At the end of the frame as), opposite the pivot 36, the frame is provided with an adjusting screw 55 for the. purpose of raising and lowering said lastnamed end. 7

Another roller 57 is carried on the frame 49 outside of the opening 47.

The above described construct-ion positions the rollers 51 inside of the channel. 4t and above the conveyor 43; and the roller 57 outside of the chamber, above the conveyor.

.The arrangen'icnt of rollers with respect to the length of the channel l-t is such that the elevation of each of the plurality of rollers is greaterthan that of the prcectlilrgf one (readingd ig. 2 from left to right). it is to be understood that any other suitable number of rollers may be used, three being shown by way of example.

The outside roller shaft 59 isdriven from the conveyor drive 61 by means of a gear drive 63 and in turn drives the rollers 51, 57 by means of a sprocket-and-ehain system 65. The gearingis such that the surfacespeeds of the rollers are about equal to the surface speed of the conveyor belt and in The idler wheel 66 driving gear 68 so as to accommodate adjustment from the screw 55.

From the above it may be seen that a large space is rovided above for permitting ufl and feather out, to form fine particles .Ild fibers. Then, as the wool rcaclr Ill) settles, the hopper sides and the wools own weight compress it gently until it rests on the moving conveyor 43. The conveyor is made of foraminous material of a rather fine mesh which permits dropping out of the line beads or balls in the blown material. The left-hand roller compresses the wool deposited ahead of it as said wool is fed thereunder by the conveyor. This puts a lower strip or layer 44 of compressed wool between the two inner rollers upon which wool 46 deposits to be compressed into a second layer 48 on said first layer 44: by the second roll. Two contiguous layers of Wool emerge from the second roller, upon which more wool 50 is deposited to be fed from out of the blow chamber and beneath the last outside compressing roller 57 to form a top layer 52. 1t is' to be understood that the compression is light and does not provide distinct layer]; in the finished sheet, although a stratifying eii'ect is hath The layers are merely referred to herein for convenience.

As stated before, as many rollers may be used as desired, depending upon the number of layers required. The slope ofthe line of rollers and distance apart govern the thickness and/or texture but this may be adjustably varied by varying the speed of the conveyor drive 45. 1 The variation in texture and/or thickness is thus had because a different time is allowed for accretion of wool as the conveyor speed is changed.

The advantage in laying the wool down in layers instead of compressing it to the desired thickness in one operation, lies in the fact that the fibers lie in more parallel plane's near the surfaces on which given accretions rest. Hence, by starting new accretions at intervals on flatter surfaces of the material itself, the most efiicient felt having fibers running substantially perpendicular to the direction of heat flow is obtained. The breaking and mashing of upstanding fibers into folded and irregular positions is also reduced. The roll pressure being light, a substantially honiogenous sheet is the final result. a r

Sometimes it is desirable to have more dense edges on a strip and these may be ob tained by introducing inwardly slanting guides ahead of each roller as illustrated in Fig. 7.- The more dense edges prevent fraying out of the material when it is handled. l

From the conveyor the material is preferably fed to a cutting plate .67 and cut into" suitable lengths .by shears 69 or other means.

Before the plate 67 is reached the sheet of wool is further impregnated" with binder -material issuing in jets 7'1, 73. The binders described herein may comprise such substances as asphalt, sodium, sihcate, casine, glue, wax or similarmaterials.

, The improved product includes the ad then down into a cradle comprising a vantages hereinbefore described. A further one rests in the manner of assembling the cut sheets ofmaterial .into an insulating block, which comprises laying down a sheet of wool, then applying a sheet 77 of less porousmaterial such as tar or roofing paper, then a sheet of wool material and so on, until a predetermined size of laminated block is formed. This block may be held in assembled position by wire stapling, sewing, gluing or wrapping. Its advantage is due to the fact that when the air in the block expands and contracts under thermal changes, the air breathing action thereot does not take moisture to the interior of the block so readily as when a non-laminated assembly is used.

It is a well known fact that the presence of moisture in the interior recesses of insulating blocks results in a lower insulat ng efliciency because of the heat transmitting characteristics of said moisture. It IS evident that the moisture cannot enter the center of the block over the short paths from the sideward faces 79, 8]. because it cannot pass through the non-porous sheets oi: tar paper or the like. In other words, the 111013- ture is forcedto take a long path IIOIII' the edges 83, of the block and for a given period of breathing will not travel as tar into the interior.

In Figure 4 is illustrated the manner in which another form of block may be constructed. In this form the strip of wool 87 manufactured in the manner previously described is fed downwardly through two lead rolls 89 and then downwardly between two guide rolls 91 linked to a reciprocating mechanism 93. The reciprocating mechanism 93 reciprocates the guide rolls 91 so that as the wool material 87 is ied downwardly it is folded back and forth in such a manner that a type of bale 95 is forined. This bale 95 is suitable for shipping purposes.

In Figure 5 is illustrated a third form in which the 1 material may be handled after leaving the blow chamber. In this case the material is fed over a main guide roll 97 and 99 and anti-friction rollers 101. The contour of the cradle is such that the material s rolled into a cylindrical shape 103. In this form it may he slipped into a paper envelope for shipment and may be. unrolled at an- .other point to .be worked into other products.

In Fi re 6 is illustrated a fourth form in which t e material may be handled. In this last case two toothed rollers are employed. The teeth of these rollers engage one another loosely so that a strip 107 of the wool material may be fed therebetween with a strip. 109 of suitablepaper or fabric. The

function of the teeth is to press the wool and paper sheets into a composite corrugated INT) sheet. The corrugated sheet is fed down a chute 111' after leaving the rolls 105. The chute 111 is providedwith a bend 113 at the lower end thereof which affords resistance to the corrugated sheet, whereby the previouslyloose corrugations are forced or pressed together in accordian-like fashion. From the bend 118 the finished corrugated product is fed to a conveyor 115 which is moving at a slower speed than the peripheral speed of the teeth on the rolls 105. The product formed by the last-named modification is especially adapted to be placed on cylindrical surfaces or other curved surfaces such as pipes and the like.

It will be seen from the above that a product is formed which is improved in several respects. It has a'better chemical composition, because itis free of sulphides; ithas better texture because of the manner in which it is laid down; and the final form of the material is better adapted to resist heat flow therethrough, especially at right angles to the sheet-into which the materialis built.

It is to be understood from the above that the introduction of the binder material at the nozzle in the steam pipe and at the jets 71,

- 73 may be omitted for certain applications of the material. I

Another point of no elty exlsts 1n the present 1nvent1on,based upon the chemical proportions of the. charge introduced into the fusion chamber or cupola 1. Up to'this point the nature of the rock charge has been only broadly outlined.

For instance, in the prior art a typical analysis of resulting rock Wool would be (more specifically) 7 Per cent Substance. by weight. Silicon oxide (SiO 40 (acid) 17 (neutral) 6 (basic) Aluminum oxide (AI O LH. Iron oxide (FeO) or (Fe O Calcium oxide. (CaU) 21 (basic) Magnesium oxide (MgO) 13 (basic) lt'liseellaneousuugu- 3 Total 100 The above list shows a ratio of one to one of silicon to basic materials. The result is that a tei'idency to slacking is had which disintegrates the wool ilrits ap flications. Another is that the wool will decompose in dilute mineral acids.

The wool material resulting in the present invention comprises a typical analysis as follows:

Percent Substance. by weight; Silicon oxide (SiO 57 (acid) Aluminum oxide (1 11 9 12 (neutral) Iron oxide (F00) 5 (basic) Calcium oxide (CaO) 15 (basic) Magnesium oxide (MgO) 9 (basic) Miscellaneous 2 Total 100 resulting wool a more hard and glassy composition which will not slack or dissolve. A

ratio of silica to basic naterials of from oneand-one-half to one, to two to one is suitable for preventing this slacking or disintegrating effect. The improved composition is at tained by .electing the proper raw material, such as by adding a high silica rock.

In view of the above, it will be seen that the several objects of the invention are achieved'and other advantageous results attained.

As many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense;

I claim:

1 The method of manufacturing molten material for rock and mineral wools com prising melting a mass of suitable raw 11151- raw material and fusing the materials in the presence of hot gases from an oxidizing flame;

4. The method of manufacturing molten material for rock and mineral wools comprising adding an oxidizing material to the raw material and melting the materials in the presence of hot gases from an oxidizing I 7 H0 flame fired in a separate compartment.

5. The method of fusing material for rock and mineral wools comprisingengendering an oxidizing flame, and fusing the raw material by passing therethrough the hot gases from said flame.

6. The method of fusing material for rock and mineral wools comprising engendering an oxidizing flame, passing the hot gases from said flame through the raw material to' fuse said raw material, and blowin the fused material into a chamber provide with a. felting conveyor and simultaneously mix ing said material with a binding material.

' Means for fusing material for rock and mineral wools comprising a fusion chamber adapted to be filled with raw material, a separate combustion chamber communicating with said fusion chamber at the lower end thereof, said combustion chamber being formed upwardly, means for engendering an oxidizing flame in-the combustion chamber and means for passing the products from said flame through said material in the fusion chamber.

8. Means for fusing material for rock and mineral wools comprising a fusion chamber adapted to be filled with raw material, a separate combustion chamber COIIlmunicating with said fusion chamber at the lower end thereof, said combustion chamber being formed upwardly, means for engendering an oxidizing flame at the inlet por tion of the combustion chamber, and means for passing the products from said flame from the combustion chamber to and through the material in said fusion chamber.

9. The method of manufacturing rock and mineral wools comprising introducing the raw material and an oxidizing agent into a fusing chamber, means for engendering a flame in a chamber, passing the products of said flame into and through the material in said fusion chamber whereby the material is melted and drawing the liquid material from the fusion chamber at a point adjacent the region of communication between the fusion and combustion chambers.

10. Apparatus for manufacturing improved rock and mineral wools comprising a fusion chamber adapted to be filled witliraw material, a separate combustion chamber communicating with said fusion chamber,

means for. engendering an oxidizing flame in the combustion chamber and means for pass ing [be hot gases from said flame through said material in the fusion chamber, a blow chamber, means for drawing molten material from the fusion chamber and blowing iibrous material into the blow chamber and a moving conveyor engaging the lower end of said blow chamber to carry out said ma terial as it settles.

11. Apparatus for manufacturing improved rockandmineral wools comprisim a fusion chamber adapted to be filled with cluding a channel, a conveyor in said channel adapted to receive settling wool and rollers placed over said conveyor in ascending elevation in the direction of conveyor movement.

In testimony whereof, I have signed my name to this specification this 31st day of December, 1926.

EDWARD R. POWELL. 

